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It may be a bit of a stretch, but it almost sounds like an example of Get Thee to a Nunnery.
If audiences of 1815 were supposed to say "Oh, Bristol! That person must have been a dirty rotten slave driver! How despicable!" while audiences of 2020 say "Bristol, huh? Never heard of it," then it fits with "at the time it meant something (typically saucy), but today the meaning has been lost."
Get Thee to a Nunnery sounds like the more applicable one, thanks! I did consider Genius Bonus too but I think that would apply to something that was written today since that one is an intentional wink to the audience.
Edited by eowynjedi
I'm looking for something that would fit this type of situation: In Emma, a character is mentioned as being from Bristol, England, which was a slave port before it was outlawed. This was an implication to contemporary readers that her fortune was basically dirty money but people from modern times gloss over the name Bristol (unless they know the history already).
It's not exactly Values Dissonance; my next best guess Unintentional Period Piece seems to be limited to more recent things that makes people go "that is so very 80's" as opposed to "this reference flies over everyone's head because it no longer applies." I used Small Reference Pools but that doesn't feel right.